may god bless the people of south africa. >> reporter: president obama and former presidents carter, clinton and george w. bush led the american delegation. during his eulogy. president obama called mandela a giant of justice. comparing him to gandhi, lincoln and dr. king. >> he changed laws. but he also changed hearts. >> reporter: the president added mandela's work is not done. >> around the world today, men and women are still in prison for their political beliefs and are still persecuted for what they look like, and how they worship and who they love. that is happening today. >> reporter: before talking about mandela's legacy of reconciliation, he shook hands with cuban leader raul castro. south african oscar winner charlize theron and proctor bono -- rock star bono were among the ones in the crowd. they came to honor and remember and celebrate a man who united a nation and inspired generations, alphonso van marsh, johannesburg south africa. >> tributes are also planned here in the united states including one this week in washington, d.c.. there the oakland based pacific boy choi